Abstract: This invention relates to improved elastomeric polyurethane compositions and seals which show increased resistance to the degrading effects of contact with fluids containing phosphate esters relative to conventional polyurethane elastomers. The elastomeric composition includes the reaction product of 3,3'-dimethyl-4,4'-diphenyl diisocyanate; one or more polycaprolactone polyols; and a chain extender which includes a linear aliphatic compound defining a chain of carbon atoms which includes at least one unsaturated carbon-carbon bond and which is terminated at each end with a hydroxyl group. An example of a preferred chain extender is 1,4-dihydroxy-2,3-dibromo-2-butene.